Computer systems typically comprise a combination of computer programs and hardware, such as semiconductors, transistors, chips, circuit boards, storage devices, and processors. The computer programs are stored in the storage devices and are executed by the processors.
One use of computer systems is in a technology known as surface based or multi-touch computing, in which users interact with a touch screen or other surface to interact with digital content through natural gestures, touch, and physical objects. The multi-touch screen accepts input from multiple users simultaneously, allowing for complex gestures, including grabbing, stretching, swiveling, and sliding virtual objects. The display area of surface-based computing devices can vary from relatively small areas, such as that of a small desk or video screen, to relatively large areas, such as a conference table surface. The multi-touch screen may use a variety of technologies, such as projectors to project images onto a surface and cameras to detect gestures.